#define _CRT_SECURE_NO_WARNINGS 1
#include"string.h"
#include<string>
namespace zkf
{
	void test1()
	{
		string s1;
		string s2("11111111");
		string s3 = s2;
		s1 = s2;
		cout << s1.tou() << endl;
		cout << s2.tou() << endl;
		cout << s3.tou() << endl;
		s3.push_back('2');
		s3 += "44444444444444454444";
		s3.append("12345");
		s3 += '9';
		string s4("hello world");
		cout << s4.size() << endl;
		s4.erase(2);
		cout << s4.size() << endl;
		cout << s4.tou() << endl;
		for (auto e : s4)
		{
			cout << e;
		}
		cout << endl;
	}
	void test2()
	{
		string s1;
		string s2("hello world");
		string s3 = s2;
		size_t i=s3.find("orld",0 );
		cout << i << endl;
		cout << s3 <<endl;
		string s4=s2.substr(5,3);
		cout << s4 << endl;
		string s5;
		cin >> s5;
		cout << s5;
	}
}
int main()
{
	zkf::test1();
	zkf::test2();
	return 0;
}